I highly doubt many people were gonna bet what $2,500 on Bret just to win $100 (I'm sure my math is off but you get the point) so if anything this site probably came out ahead from people throwing down a lil coin on HBK/Vince. I think we forget the % of smart marks/Internet fans is nothing compared to the "regular" fans.
Don't forget websites take bets on The Oscars and on reality TV shows.Those are usually taped months in advance so other than live finales it's possible for those winners to leak as well.